Yes, I have tried to replace the batteries in both (original OEM) 2009 S40 keys. Both keys will start the car without issue, but I cannot lock/unlock with either key button.

When I replaced the S40 battery a few months back, I was hoping that "reset" of a battery disconnect & replacement may help- but the issue did not resolve.

When I manually unlock the car with the physical key (from inside fob) the alarm sounds. When I start the car, the alarm ends. It's functional, but a pain.

I've heard stories about other cars having a bad sensor (inside the actual car) with a $1000+ repair tag.

Any ideas or experiences?

Thank you in advance

 

Is your cat keyless drive?